Outstanding Performance of Magnetically Separable Sulfureted MoO3/Fe-Ti Spinel for Gaseous Hg0 Recovery from Smelting Flue Gas: Mechanism and Adsorption Kinetics.

To replace the hazardous and complicated Boliden-Norzink technology, the technology of Hg0 recovery from smelting flue gas by a magnetic and reproducible sulfureted MoO3/Fe-Ti spinel was employed to keep the produced H2SO4 free of Hg. The sulfureted MoO3/Fe-Ti spinel showed excellent performance in capturing gaseous Hg0, with an average adsorption rate of 93.3 μg g-1 min-1 and an adsorption capacity of 66.3 mg g-1 at 60 °C, which were much better than those of most of the other reported sorbents. Meanwhile, the sulfureted MoO3/Fe-Ti spinel exhibited excellent superparamagnetism and magnetization of 19.9 emu g-1, which ensured that it could easily be magnetically separated without a specialized precipitator or the molding of pulverous sorbents to monolithic sorbents. To investigate the promotion mechanism of MoO3 loading on Hg0 adsorption onto the sulfureted Fe-Ti spinel, the Hg0 adsorption kinetic parameters of the sulfureted MoO3/Fe-Ti spinel and sulfureted Fe-Ti spinel, resulting from the fitting of the adsorption breakthrough curves based on the kinetic model, were compared. The promotion of MoO3 loading was attributed to the remarkable increase in the adsorption sites on the sulfureted Fe-Ti spinel for Hg0 physical adsorption, which was mainly related to the formation of the MoS3 layer.